The constructions of mailpieces and envelopes must conform to specified size and flexiblity requirements. Postal services, like the United States Postal Service, sort large volumes of mail with high-speed automated processing equipment having pairs of vertical moving belts arranged in a network to grip and serially transport individual mailpieces at a speed of up to 40,000 pieces an hour. The moving belts convey the mailpieces, which are oriented vertically, at a linear velocity approaching 500 to 600 feet per minute. Each mailpiece is oriented in a vertical plane such that a three (3) inch edge portion of the mailpiece is gripped between the moving belts. An optical scanner provided adjacent to the moving belts identifies a destination address for each mailpiece. Mailpieces are sorted according to the destination address and routed by the network of moving belts into assorted bins or stackers.
Changes in direction of transported letter mail in automated processing equipment are accommodated by providing a pulley, roller or drum over which the moving belts are trained at the point where the direction change is to occur. For example, if the mailpiece is moving linearly in a horizontal direction and it is desired to effect a directional change to a different horizontal direction, a drum mounted for rotation about a vertical axis is placed at the change-of-direction point in the path of travel of the opposed belts between which the mailpiece is gripped for transport. As the belts move about the rotating drum, the mailpiece travels through a curved path conforming to the drum periphery and emerges traveling between the moving belts in a new horizontal direction.
Breakable, frangible or stress-sensitive articles, such as compact disks or mini-compact disks must be packaged inside a mailer. Letter-size mailers should comply with postal regulations, such as size requirements and address positioning, while protecting the stress-sensitive article from damage during sorting by the automated processing equipment. Moreover, postal regulations would require the mailer to be flexible enough to be bent and routed about the circumference of cylindrical pulleys, rollers and drums of the type used in automated processing systems at locations where directional changes occur in the travel path of the belts.
Conventional mailers would expose stress-sensitive articles to a significant risk of damage as the mailer is bent about the circumference of the cylindrical roller or drum. As the mailer is conveyed about the exterior of the pulley, roller or drum, the stress-sensitive article must curve or bow and will experience a state of tension due to the flexure that can damage or even break the article. Thus, because of this and other significant shortcomings, conventional letter-sized mailers do not adequately safeguard stress-sensitive articles when handled by automated processing equipment of the type used by the United States Postal Service.
If the dimensions of the mailer exceed a maximum dimension (e.g., oversized) as governed by postal regulations or does meet the flexibility requirements for letter sorting equipment, the United States Postal Service does not treat the mailer as a letter. Instead, the mailer is handled as a non-letter or flat by automated equipment that does not require routing about the exterior of a drum. Most mass mailings, however, are of pre-sorted, letter-sized mailers that are less expensive to mail.
Accordingly, there is a need for mailers for articles that can be handled by automated letter-sized processing equipment and that are fully compliant with postal regulations while simultaneously protecting the article from damage during processing.